data-consistency

What algorithm to use to calculate a check digit for a list of digits? The length of the list is between 8 and 12 digits. see also: How to generate a verification code/number? The Luhn algorithm is good enough for the credit card industry... As RichieHindle points out, the Luhn algorithm is pretty good. It will detect (but not correct) any one error or transposition (except a transposition of 0 and 9). You could also consider the algorithm for ISBN check digits , although for old-style ISBN, the check digit is sometimes "X", which may be a problem for you if you're using integer fields. New

I wonder how reliable the adler32 checksum is, compared to e.g. md5 checksums? It was told on wikipedia that adler32 is "much less reliable" than md5, so I wonder how much, and in which way? More specifically, I'm wondering if it is reliable enough as a consistency check for long-time archiving of (tar) files of size 20GB+? For details on the error-checking capabilities of the Adler-32 checksum, see for example Revisiting Fletcher and Adler Checksums. Maxino, 2006. This paper contains an analysis on the Hamming distance provided by these two checksums, and provides an indication of the

I have read noumerous threads and watched many videos on combining Dropbox and Git functionality. One such thread is this: Using Git and Dropbox together effectively? Here is what i want to do: I am currently working on a large personal project (only me, no need for encryption). Work is done on two desktop computers (Win 7, Ubuntu) and one laptop (OSx). I wish to have my files accesible from anywhere and under version control (git) It would be great to have web-access to all the files (trough Dropbox.com), so there would be no need to install Git if I were to eg. borrow a computer. Most of the

A number of the developers here are having a friendly (some would say religious) discussion about whether a GET request from a RESTful API should return the ID of the requested resource . Let's assume the following GET request: http://my.api.com/rest/users/23 This currently returns: {"name": "Jim", "age": 40, "favoriteColor": "blue"} Note that "id" is missing from the result set. There are basically 4 camps battling with this issue. CAMP #1: When callers make the GET request, they already know the ID. Therefore, the result set should not include the ID. If callers need this data to enable UI

While each microservice generally will have its own data - certain entities are required to be consistent across multiple services. For such data consistency requirement in a highly distributed landscape such as microservices architecture, what are the choices for design? Of course, I do not want shared database architecture, where a single DB manages the state across all the services. That violates isolation and shared-nothing principles. I do understand that, a microservice can publish an event when an entity is created, updated or deleted. All other microservices which are interested in

I'm new in Cassandra and I've read that Cassandra encourages denormalization and duplication of data. This leaves me a little confused. Let us imagine the following scenario: I have a keyspace with four tables: A,B,C and D. CREATE TABLE A ( tableID int, column1 int, column2 varchar, column3 varchar, column4 varchar, column5 varchar, PRIMARY KEY (column1, tableID) ); Let us imagine that the other tables (B,C,D) have the same structure and the same data that table A, only with a different primary key, in order to respond to other queries. If I upgrade a row in table A how I can ensure